Abstract: Postnatal development includes progressive and regressive brain changes, some of them dependent on experience. Using a natural model of congenital deafness, the deaf white cat, our team has focused on effects of sensory experience on the structure and function of the auditory system. We use cochlear implants to test the auditory function in deaf animals and provide deaf animals with a portable signal processor and a cochlear implant to initiate hearing experience at different ages. We could demonstrate deficits in cortical maturation and a delayed and altered cortical synaptic development in congenital deafness. Reduced feature sensitivity, as we have further shown, complicates the starting point for learning after restoration of hearing. Chronic electrical stimulation prevented many of the maturational deficits, provided stimulation was initiated within early sensitive periods. We further studied visual function of the cortical auditory areas in deafness and demonstrated an areal-specific crossmodal reorganization. Although in the reorganized areas the auditory responsive neurons were not significantly reduced in number, recruitment of neurons for visual tasks likely reduces the auditory computational capacity in the given area. Finally, corticocortical connections were studied both anatomically and functionally. Based on our layer-specific recordings in primary auditory cortex we previously suggested a corticocortical decoupling in deafness. Using tracer experiments and functional studies we find reduced bottom-up and top-down cortical information transfer in deafness. Such compromised top-down processing in the auditory cortex is likely participating on the closure of sensitive periods.

Bio: Andrej Kral was born in Bratislava, studied general medicine at the Comenius University (MD 1993, PhD 1998). His first research position was at the Institute of Pathological Physiology (1992 – 1995). In collaboration with the Mathematical Institute (Prof. V. Majernik) he worked on computer models of neuronal networks. In 1995, at the Institute of Sensory Physiology, J.W.Goethe University, Frankfurt am Main (Head: Prof. R. Klinke) the focus of research moved to cochlear implants. He was appointed associate professor of physiology (“Priv.-Doz.”) at J.W.Goethe University in 2002. In 2004 he was offered a position of a tenured professor of neurophysiology at the Institute of Neurophysiology, University of Hamburg. Since 2009 he has been Chair and Professor of Auditory Neurophysiology at the Medical University Hannover and the director of research of the ENT clinics. Andrej Kral leads the Dept. of Experimental Otology and the Institute of AudioNeuroTechnology. Since 2004 he has been Adjunct Professor of Neuroscience and Cognition at The University of Texas at Dallas, USA. The focus of research includes neuroscience of deafness, cochlear implants, auditory development, brain plasticity, cross-modal reorganization and neuroprosthetic stimulation. The research has been published, among others, in New England Journal of Medicine, Science, Lancet Neurology, Nature Neuroscience, Trends in Neuroscience, Brain, Journal of Neuroscience and Cerebral Cortex, he gave more than 100 invited talks at international conferences and institutes in US and Europe. Together with A.N.Popper and R.R.Fay he edited the volume of the Springer Handbook of Auditory Research on Deafness (vol. 47). The lab received funding from German Research Society (DFG), Common Scientific Conference Germany, State of Hamburg and State of Lower Saxony, NIH, EU and cochlear implant companies.

Who should come: hearing, speech and language researchers and clinicians, cognitive scientists, psychologists, researchers in aging health and health care professionals.
Network: Learn from one another and see what collaboration opportunities are available.
Registration: Entry is free and open to the public. Please register by Monday 6 March 2017 to louise.dodd@mq.edu.au